The labelled quantity has been rounded to the nearest ml
The actual quantity will be between 249.5000 and 250.4999 (7 sf)
This can also be written as 249.5 <= x < 250.5
Or as the interval [249.5, 250.5) which means from 249.5 (including 249.5) to 250.5 (excluding 250.5)
If the quantity was 250.5 it would round up to 251.
